/**
 * @author gcc
 * @date 2014-08-22
 */
package com.chnbst.bstyun.core.common;
/**
 * 创建随机生成数工具类
 * @author gcc
 *
 */
public class CreateRandom {
	/** 
	  * 创建指定数量的随机字符串 
	  * @param numberFlag 是否是数字 
	  * @param length 
	  * @return 
	  */  
	 public static String createRandom(boolean numberFlag, int length){  
	  String retStr = "";  
	  String strTable = numberFlag ? "1234567890" : "1234567890abcdefghijkmnpqrstuvwxyz";  
	  int len = strTable.length();  
	  boolean bDone = true;  
	  do {  
	   retStr = "";  
	   int count = 0;  
	   for (int i = 0; i < length; i++) {  
	    double dblR = Math.random() * len;  
	    int intR = (int) Math.floor(dblR);  
	    char c = strTable.charAt(intR);  
	    if (('0' <= c) && (c <= '9')) {  
	     count++;  
	    }  
	    retStr += strTable.charAt(intR);  
	   }  
	   if (count >= 2) {  
	    bDone = false;  
	   }  
	  } while (bDone);  
	  
	  return retStr;  
	 } 
}
